Electronic devices are programmed and controlled by various methods. One commonly used method to program or control electronic devices involves the use of potentiometers, particularly adjustment potentiometers. Potentiometers are widely used as user controls, and may control a very wide variety of equipment functions. The widespread use of potentiometers in consumer electronics has declined in the 1990s, with digital controls now more common. However they remain in many applications, such as volume controls and as position sensors. Potentiometers are also used to program or set power supply set-points in various electronic devices, such as in night vision imaging devices.
The use of potentiometers or other such control assemblies requires a break-through of the equipment housing to enable the programming or controlling functionality. This break-through presents an ingress for environmental contamination of the internal electronics. For example, if the potentiometer is not properly sealed, moisture may enter the housing and damage internal electronics. This presents a critical risk for electronic devices that may be exposed to the weather and which need to ensure accurate functionality even in the face of difficult environmental conditions. Additionally, potentiometers have a mechanical interface which can be damaged during set-up or on-going operation. For example, the potentiometer may be rendered nonfunctional by breakage of the adjustment screw. Such damage could leave the electronic device inoperable in critical situations, when it is most needed to accurately function. Furthermore, the use of potentiometers to program and control electronic devices leaves the internal electronics subject to unintentional or unwanted readjustment or tampering. For particular electronic devices, such as night vision imaging devices, the potential for unwanted access to the potentiometer and for reconfiguration of settings to the internal electronics presents an unnecessary and intolerable security flaw. As such, particular electronic assemblies can not suitably employ potentiometers.
Remote, or contactless, mechanisms have presented a useful alternative to potentiometers for programming and controlling electronic devices. Remote systems may employ technologies such as infra-red to program and control electronics contained within a sealed housing, removing the need for physical contact between the control assembly and the internal electronics. Electronic devices which employ a remote system for programming and control may utilize a transmissive interface, such as a window or port, which enables such contactless control. While the remote mechanisms reduce or eliminate the potential for the electronic devices to be damaged or tampered, it remains important that the control interface be properly sealed to avoid ingress of environmental contaminants, such as moisture. A liquid-tight sealed assembly may be preferably utilized in electronic devices that are subject to, and are needed to perform without failure, under difficult environmental conditions. Environmental contamination, such as moisture, to the internal electronics of these devices, such as night vision imaging devices, can render the electronics inoperable when they are most needed.
Night vision imaging devices are used in a myriad of environmental conditions. Night vision goggles (NVG), utilize internal electronics such as image intensifiers to make objects visible in low-light situations. Image intensifier devices are employed in night visions systems to convert a dark environment to a bright environment that is perceivable by a viewer. Night vision systems have industrial, commercial and military applications. The image intensifier device collects tiny amounts of light in a dark environment, including the lower portion of the infrared light spectrum, that are present in the environment but imperceptible to the human eye. The device amplifies the light so that the human eye can perceive the image. The light output from the image intensifier device can either be supplied to a camera, external monitor or directly to the eyes of a viewer.
Image intensifier devices generally include three basic components mounted within an evacuated housing, namely, a photocathode (commonly called a cathode), a microchannel plate (MCP) and an anode. The photocathode is a photosensitive plate capable of releasing electrons when it is illuminated by light. The MCP is a thin glass plate having an array of channels extending between one side (input) and another side (output) of the glass plate. The MCP is positioned between the photocathode and the anode. The three basic components of the image intensifier device are positioned within an evacuated housing or vacuum envelope. The image intensifier device is generally capable of being programmed and controlled prior to and/or during operation. A system for programming and controlling the internal electronics of an electronic device remotely, without the need for a breakthrough of the housing, would eliminate the potential for damage by breakage of the controls, tampering of the programming, and/or environmental contamination to the electronics.